Heat treatment of thermoplastic or thermosetting yarn



1960 R. s. GILCHRIST ETAL 2,958,921

HEAT TREATMENT OF THERMOPLASTIC OR THERMOSETTING YARN Filed Nov. 25, 1955 INVENTORS REGINALD Sfimcumn k ERNEST P Samw DEms ABNma'msu ATToRNEYs United States Patent 2,958,921 HEAT TREATMENT OF THERMOPLASTIC OR THERMOSETTING YARN Reginald Selby Gilchrist, Broadstairs, Ernest Phillip Scragg, Macclesfield, and Denis Albert Edward Mattingly, London, England, assignors to The Klinger Manufacturing Company, London, England, and Ernest Scragg & Sons Limited, Macclesfield, England, both British companies Filed Nov. 25, 1955, Ser. No. 549,091 7 Claims priority, application Great Britain Nov. 26, 1954 11 Claims. (Cl. 28-62) This invention relates to heat treatment of thermoplastic or thermosetting yarn of the 'kind in which the yarn is continuously drawn over a heated surface. In order that the characteristics of the yarn so treated may be constant over the whole of its length it is important that the heated surface should be maintained at a constant temperature within comparatively fine limits and in the case where the heated surface is of considerable extent so as to enable a number of yarns to be simultaneously treated it is important that the same constant temperature should be maintained for all the yarns so that they may have the same characteristics. An object of the present invention is to provide an apparatus which will fulfill the above requirements.

According to this invention an apparatus for the treatment of thermoplastic or thermosetting yarn comprises a hollow body having a smooth surface over which the yarn may be continuously drawn, means forcirculating fluid through "said hollow body, fluid, and a thermostat controlling said heating means.

Preferably the means for-heating the fluid is located within said hollow body.

The heat responsiveelement of the thermostat may be located in said fluid within the hollow body.

The means for circulating the fluid in said hollow body may form a closed fluid circuit disposed substantially wholly within the body.

The fluid preferably comprises a non-carbonising oil of low vapor pressure.

An expansion vessel for the fluid may be arranged above said hollow body and connected therewith by a conduit.

The hollow body may comprise a pipe the interior of which is formed with passages communicating directly with one another at one endand connected ,at the other end respectively with the inlet and-outlet of a pump.

A second pipeof smaller diameter may be arranged within'the first said pipe so thatthe space between them forms one passage and the bore of the smaller pipe forms the other passage. I

The aforesaid pump may comprise a submerged centrifugal pump disposed in ,a compartment atone end .of said pipe.

Other features of the invention are set outin the following claims and description which is made with reference to the accompanying drawings in which:

Figure 1 is a part vertical section and part elevation through an apparatus suitable for treating a number of yarns, a

Figure 2 isa diagrammatic side elevationfof the apparatus looking from the right of Figurel; and

"Figure 3lis' a diagrammatic cross section thridugh of theheating elements-forthe yarn. i .1 ,1.

In the construction shown in the drawing four heating devices for four separate yarns are provided each of which comprises a curved tongue of metal such as copper or brass and which tongues are brazed to a pipe 11 containing hot liquid so as to be spaced apart thereon.

one

means for heating saidv be about rising to Each of the curved tongues is provided with a V section groove 12 extending along the length thereof and through which the yarn 13 shown in Figure 3 can be drawn. The tongues may be solid or may be hollow so as to receive the hot liquid.

Arranged respectively above and below each tongue are two pulleys 35 and 36 and between the upper pulley and tongue is a twisting head 18. For example each twisting head may be provided with two hollow trunnions and means are provided for driving the head about an axis co-axial with the trunnions. The head carries a pulley or the like arranged with its axis transverse to the axis of rotation and so disposed in relation to the trunnions that the yarn passes from one trunnion around the pulley and then out through the other trunnion.

The yarn is drawn upwardly over a tongue 10 by the uppermost pulley 35 or by a bobbin associated therewith. With this arrangement the yarn is twisted while in an unset condition and is then set, whereaiter it is untwisted so as to impart to it a torsional strain which process is known as false twisting. Certain yarns may require to be stretched as they pass over the heated surface or may require to have slack taken up for which purpose the yarn may be arranged to extend through known tensioning means (not shown) on the inlet side of the apparatus or the upper pulley 35 is driven at a greater speed than the lower pulley 36. With other yarns, tension therein may require to be relieved as the yarn passes over the heated surface, in which case the bottom pulley may be driven faster than the upper one. For yet other yarns the uper and lower rollers may be driven at the same speed. I

Preferably the yarn is treated with a setting agent which in the case of nylon may be water which maybe applied, before and/ or while passing over the heated sur-'- face, for example the yarn may be wound around a pulley (not shown) dipping into a water tank or may be sprayed, with water, or each tongue is provided with a small passage 16 leading from a water supply pipe 17 to the bottom of the groove therein. The passage may open into the groove at a position where the temperature is just below the boiling point of water. Means may be provided for maintaining the moisture or steam around the yarn during the passage of the yarn along the groove also for preventing heat losses due to convection or radiation or due to the entry of air along the groove. For these purposes a flap 14 may be hinged to the upper end of each tongue and shaped to the contour of the tongue, and may project partly into the groove. Each tongue and flap is heat insulated at 15.

Means may be provided for cooling the yarn as it leaves the tongues for example a jet of air may be directed on to it or a fan may promote a general flow of cool air above the tongues.

The mouth of each V groove is closed by a plate 14 and the combination may beqenclosed within suitable lagging. The tongues receive sufficient heat from the hotliquid'in the pipe that the temperature at the upper end is appropriate for setting the yarn and is above the boiling point of water while the temperature at the lower end is below the boiling point of water.

In an apparatus for treating nylon yarn of 60 denier suitable lengths and widths of cross section area 5? each tongue is 12".long and /2" square. The temperature at the outer or lower end, of each tongue is arranged to over the first 3" and then about 200 C. over the next two inches and rises to 230 C. over about the next /2" and which temperature remains constant for the rest of the length of the tongue. The rate of traverse of the yarn over each tongue is Patented Nov. 8, 1960 about 100 feet per minute. As previously indicated the tongues are brazed to the pipe 11. The pipe is closed at one end and is connected at the other end to a wall of a compartment 21, Disposed within the pipe 11 is a smaller pipe 22 open at the end adjacent the closed end 20 of the other pipe and connected at the other end to the outlet of a centrifugal pump casing 23. An electric heating element 24 extends along thespace between the two pipes and is supported by suitable insulated supports 26 from the smaller pipe 22. The heat responsive element 27 of a thermostat projects into the pipe 22 close to where it joins the outlet of the centrifugal pump casing. The. compartment 21, within which the centrifngal pump is disposed, is connected by an upwardly extending pipe 28 with an expansion chamber 29. The rotor 30 of the centrifugal pump is fixed to a shaft 31 which extends up through the pipe 28 and out through the top of the expansion chamber 29. The leads 32 for the, electric element 34 pass up through a tube 33 Within the pipe 28 and thence out through the top of the expansion chamber 29 and are connected to a controller hereinafter described. The two pipes 11 and 22 and the chamber 21 are filled with a noncarbonising oil of low vapour pressure such as is sold under the trade name Valvata No. 29 and a column of this oil; extends up through the pipe 28 and partly fills the expansipncharnber 29. The centrifugal pump promotes a closed circuit of oil through the two pipes 11 and 22 as indicated by the arrows and it will be seen that this closed circuit is located substantially wholly within the pipe 1 1. V In an alternative arrangement the pipe 22 may be arranged coaxially with the pipe 11 and the heating element 2 may be wound around the pipe 22 which is provided with suitable electrical insulation. A number of such pipes 11 and associated parts are provided and each of the various responsive elements communicate with a controller 34 common to themall. Each heat responsive element controls a switch in circuit with its electric element 24 through the controller so that all the switches are closed at a predetermined temperature. Time control means may be associated with said switches so that they are successively brought into circuit with a sourceof supply and thus energised heating elements 24 if the heat responsive element is below a certain temperature. Theheat responsive element may be disposed in positions other than that shown in the drawing.

We claim:

1. An apparatus for the heat treatmentof a, plurality ofyarns comprising a tubular body, a plurality of tongues each attached at one end to said tubular body in good thermal contact therewith and so that the tongues are spaced apart along the length of the tubular body, said tongues having smooth surfaces over which the yarns may be drawn, means for circulating heating fluid through said tubular body, means for causing said heating fluid to flow along the tubular body across the ends of the tongues, and thermostatic means for maintaining the temperature of said fluid substantially constant.

2. An apparatus according to claim 1, wherein said fluid comprises a non-carbonizing oil of low vapourpressure.

3. An apparatus according to claim 1, including an expansion chamber for. the heating, fluid arranged above the. tubular body and connected thereto by a downwardly extending conduit.

4. An apparatus according to claim 1, wherein said tubular body comprises a first pipe closed at one end, and a seed d pipe of smaller diameter than and ar-. ranged Within the first, one end of said second; pipe terminating adjacenttheopen end of said first pipe. and.

communicating with said open end, the other end of said second pipe terminating just short of the closed end of said first pipe and communicating with the interior of said first pipe adjacent said closed end and wherein a pump having its inlet and outlets is connected respective y totheiopcn end of said first pipe and the associated end of said second pipe.

5. An apparatus according to claim'4, wherein said open. end of the first pipe and the associated end of the second pipe open into a common compartment and said pump is a centrifugal pump which is submerged in that compartment.

6. An apparatus according to claim 5, including an expansion chamber-for the heating fluid arranged above the tubular body andv connected to said'compartment by a downwardly extendingconduit and wherein a shaft for driving the centrifugal pump extends through said conduit.

7 An apparatus according to claim 5 including means for heating the fluid comprises an electric element mountted on the second pipe and extending along the length thereof.

8. An apparatus for the heat treatment of a plurality of yarns comprising a tubular body having a closed end at one end thereof, a plurality of grooved tongues secured in spaced relation on the outside of the tubular body in thermal contact therewith and arranged at approximately right angles to the body, a pipe in the tubular body and extending from the other end thereof to near the closed end and spaced from said closed end, a heating element in the tubular body adjacent said pipe, means at the said other end of the tubular body and communi cating with the pipe to force a fluid through the pipe and out of the, end adjacent the closed end of the tubular body and then along the heating element back to the said means to thereby form a closed fluid circuit for transfer of heat to thetongues and the yarn passing therethrough, and means mounted above the first-mentioned means to actuate the latter.

9. An apparatus for the heat treatment of a yarn comprising a tubular body having a closed end at one end thereof, at least one grooved tongue secured on the outside of the tubular body in heat transfer contact therewith, a pipe arranged in the tubular body in parallel relationship therewith and extending from the other end thereof to near the closed end and spaced from said closed end, a heating element in the tubular body adjacent and parallel to said pipe, and a pump at the said other end of the tubular body and communicating with the pipe to force a fluid through the pipe and out of the end adjacent the closed end of the tubular body and then along the heatingelement back to the pump to thereby form a closed fluid circuit for transfer of heat to the tongue and the yarn passing therethrough.

10. An apparatus according to claim 9, in which a shaft is provided on the said other end of the tubular body and adjacent-the P mp and having means therein to rot the p mp.

11. An apparatus according to claim 9, in which the heatingelement i s in the form of an electric heating element'and inwhich 'ashaft is provided. on the said other end'of thetubular body and adjacent thepump and having means therein to rotate the pump and to convey electric current to the heating'element.

References Cited in the file of this patent UNITED, sirafrns.v PATENTS 1,442,858,: Claypoole. Jan. 23, 1923 2,199,411 Lewis r...--..-;-...-..--.. May 7, 1940v 

1. AN APPARATUS FOR THE HEAT TREATMENT OF A PLURALITY OF YARNS COMPRISING A TUBULAR BODY, A PLURALITY OF TONGUES EACH ATTACHED AT ONE END TO SAID TUBULAR BODY IN GOOD THERMAL CONTACT THEREWITH AND SO THAT THE TONGUES ARE SPACED APART ALONG THE LENGTH OF THE TUBULAR BODY, SAID TONGUES HAVING SMOOTH SURFACES OVER WHICH THE YARNS 